some solutions to this error message:
http://fix-your-printer.blogspot.fr/2012/11/solving-error-message-clean-sensor-on.html
Good luck !
Jann31, November 2012
dddd
fff, June 2012
under the front cover there is a white plastic 'finger' lever, directly below the left hand side of the epson badge.
flick this to the left several times and...hey presto! worked for me.